1. Field of the Invention
The present invention relates to a lens-fitted photographic film unit, and more particularly to an improvement of a film unit in which a photographic film is pre-loaded without utilizing a film cassette.
2. Description of the Related Art
Lens-fitted photographic film units (hereinafter referred to as "film units") are currently on the market, e.g., under the trademark "Quick Snap" (manufactured by Fuji Photo Film Co., Ltd.). Such film units are a single-use camera pre-loaded with photographic film. These film units make it possible to take pictures whenever desired without the need for purchasing or carrying an expensive and heavy camera. The film unit in its entirety is forwarded to a photo laboratory after all frames on a photographic filmstrip (referred to as "film" herein) have been exposed. An operator at the laboratory unloads a cassette containing the exposed film from the film unit and subjects it to development and printing in accordance with conventional photographic processing techniques. The user receives photoprints and the negative film, but the film housing of the film unit is not returned. Such a film unit can take pictures of a reasonable quality in spite of its low cost.
The above type of film unit contains a film cassette, which is, however, disadvantageous in that the film housing must be disassembled or broken, at least partly, before unloading the cassette. Therefore, the efficiency of the developing process is lowered. As suggested in U.S. application Ser. No. 07/717,344, the present applicant has proposed an improved film unit containing the photographic film without the use of a cassette and provided with a structure by which the film as exposed can be easily removed from the film unit.
Such a film unit has a main body in which a lens, a film wind-up wheel, and a shutter mechanism are incorporated. The main body is provided with a film supplying chamber and a film take-up chamber formed on opposite horizontal sides of an exposure station. The unexposed film is in the form of a roll, with a trailing end thereof contained in the film supplying chamber and a leading end anchored on a spool disposed in the film take-up chamber. A user who uses the film unit operates the film wind-up wheel and winds up the film, frame by frame, after each exposure onto the spool contained in the film take-up chamber. After all the frames have been exposed, the full strip of the film is wound up in the film take-up chamber up to the trailing end of the film. When the exposed film is to be removed from the film housing, the spool is rotated in the unwinding direction, or in reverse. During the reverse rotation, the trailing film end is directed to an outlet slot formed on the body of the unit and exits therethrough. The cassetteless film unit is advantageous in that it allows for efficient handling in photo laboratories and a reduction in waste products.
There is, however, a problem in the above-mentioned cassetteless film unit. In particular, the trailing film end must be directed to the outlet slot before it can exit outward therefrom. The inside of the film take-up chamber is provided with a guide structure which directs the first film end toward the outlet slot in accordance with the reverse rotation of the spool. However, occasionally the guide structure fails to guide the trailing film end. Further rotation of the spool in the reverse direction sometimes causes the guide structure to properly guide the trailing film end. However, at times the trailing film end is caused to return toward the exposure station by entering a chamber entrance defined in the upstream position of the film take-up chamber. If the trailing film end returns towards the exposure station, it might get caught in the exposure station or stuck on a sprocket unit it jams. In such a case, considerable damage can be imparted to the film. Also, when such a malfunction occurs, the outlet structure for exiting the film is of no use and the film housing must be disassembled or broken in a darkroom, which is an extremely laborious manual operation.